1. Field of the Invention
The present invention relates to an image forming apparatus, a method for controlling the image forming apparatus, and a program.
2. Description of the Related Art
Image forming apparatuses are provided with a standby mode in which driving devices such as a printing mechanism unit are stopped and a cooling fan is placed in a non-operating state to consume a lower power. In the standby mode, the image forming apparatus can stand by in a silent state. In the standby state, when job is input via a network, the image forming apparatus immediately returns to a normal operation mode, and processes the job. Japanese Patent Application Laid-Open No. 2004-222234 discusses a method of returning to a normal operation mode only a necessary mechanism such as a printer unit in an image forming apparatus at the time when the image forming apparatus returns to the normal operation mode.
As a psychophysical law relating to human perception, the Weber-Fechner law is known. The law states that the intensity of human perception to a stimulus increases in proportion to the logarithm of the magnitude of the stimulus. That is, for example, in a case of a sound level, although an absolute value of a sound level increase is the same, a change from a silent state to a low-sound level is more noticeable than a change from a middle-sound level to a high-sound level.
When the image forming apparatus returns from the standby mode, which is a low power consumption state, to the normal operation mode, a central processing unit (CPU), a printer unit, and other devices can simultaneously return to a normal operation. In the actual operation, however, the main CPU is activated first, and the cooling fan starts rotation, and then, the printer unit starts to operate. Consequently, the respective return operation start timing is different. In other words, for example, in a series of return operations, there is a plurality of points at which the sound levels largely change from the silent state to the low-sound level, from the low-sound level to the middle-sound level, and from the middle-sound level to the high-sound level. As a result, according to the Weber-Fechner law, a user notices the sound changes many times, and this gives the user uncomfortable feelings depending on the amounts of the sound changes.
The present invention is directed to providing a mechanism for reducing change in a level of operation sound generated at the time when an image forming apparatus starts image forming, by delaying timing for driving a fan for cooling a CPU as much as possible, depending on a received job, in a second power state which is lower in power consumption than a first power state.